Proton translocation coupled to electron transfer reactions in terminal oxidases

Terminal oxidases are the final proteins of the respiratory chain in eukaryotes and some bacteria. They catalyze most of the biological oxygen consumption on Earth done by aerobic organisms. During the catalytic reaction terminal oxidases reduce dioxygen to water and use the energy released in this process to maintain the electrochemical proton gradient by functioning as a redox-driven proton pump. This membrane gradient of protons is extremely important for cells as it is used for many cellular processes, such as transportation of substrates and ATP synthesis. Even though the structures of several terminal oxidases are known, they are not sufficient in themselves to explain the molecular mechanism of proton pumping. In this work we have applied a complex approach using a variety of different techniques to address the properties and the mechanism of proton translocation by the terminal oxidases. The combination of direct measurements of pH changes during catalytic turnover, time-resolved potentiometric electrometry and optical spectroscopy, made it possible to obtain valuable information about various aspects of oxidase functioning. We compared oxygen binding properties of terminal oxidases from the distinct heme-copper (CcO) and cytochrome bd families and found that cytochrome bd has a high affinity for oxygen, which is 3 orders of magnitude higher than that of CcO. Interestingly, the difference between CcO and cytochrome bd is not only in higher affinity of the latter to oxygen, but also in the way that each of these enzymes traps oxygen during catalysis. CcO traps oxygen kinetically - the molecule of bound dioxygen is rapidly reduced before it can dissociate. Alternatively, cytochrome bd employs an alternative mechanism of oxygen trapping - part of the redox energy is invested into tight oxygen binding, and the price paid for this is the lack of proton pumping. A single cycle of oxygen reduction to water is characterized by translocation of four protons across the membrane. Our results make it possible to assign the pumping steps to discrete transitions of the catalytic cycle and indicate that during in vivo turnover of the oxidase these four protons are transferred, one at a time, during the P→F, F→OH, Oh→Eh, and Eh→R transitions. At the same time, each individual proton translocation step in the catalytic cycle is not just a single reaction catalyzed by CcO, but rather a complicated sequence of interdependent electron and proton transfers. We assume that each single proton translocation cycle of CcO is assured by internal proton transfer from the conserved Glu-278 to an as yet unidentified pump site above the hemes. Delivery of a proton to the pump site serves as a driving reaction that forces the proton translocation cycle to continue.

Long-term results of operative treatment for Hirschsprung's disease and internal anal sphincter achalasia

The aim of the study was to evaluate long-term results of operative treatment for Hirschsprung's disease(HD) and internal anal sphincter achalasia. Fecal continence and quality of life were evaluated by a questionnaire in 100 adult patients who had undergone surgery for HD, during 1950-75. Fecal continence was evaluated using a numerical scoring described by Holschneider. Fifty-four of the 100 patients underwent clinical examination, rigid sigmoidoscopy and manometric evaluation. In anorectal manometry basal resting pressure(BRP)and maximal squeeze pressure(MSP) were measured and voluntary sphincter force(VSF) was calculated by subtracting the BRP from MSP. The results of operative treatment for adult HD were compared with the results of the patients operated in childhood. In adult HD the symptoms are such mild that the patients attain adolescence or even adulthood. The patients with HD and cartilage-hair-hypoplasia were specifically evaluated. The outcome of the patients with internal anal sphincter achalasia operated on by myectomy was evaluated by a questionnaire and continence was evaluated using a numerical scoring described by Holschneider. Of the 100 patients operated on for HD 38 patients had completely normal bowel habits. A normal or good continence score was found in 91 our of 100 patients. Nine patients had fair continence. One of the patients with fair continence had Down's syndrome and two were mentally retarded for other reasons. Only one patient suffered from constipation. In anorectal manometry the difference in BRP between patients with normal and good continence was statistically significant, whereas the difference between good and fair continence groups was not statistically significant. The differences on MSP and VSF between patient groups with different continence outcome were not statistically significant. The differences between patient groups and normal controls were statistically significant in BRP and MSP. In VSF there was not statistically significant difference between the patients and the normal controls. The VSF reflects the working power of the muscles including external sphincter, levator ani and gluteal muscles. The patients operated at adult age had as good continence as patients operated in childhood. The patients with HD and cartilage-hair-hypoplasia had much more morbidity and mortality than non-cartilage-hair-hypoplasia HD patients. The mortality was as high as 38%. In patients with internal anal sphincter achalasia the constipation was cured or alleviated by myectomy whereas a significant number suffered from soiling-related social problems.

Monimuotoisuus ja esteettömyys : Näkövammaisten asiantuntijoiden työelämäkokemuksia

The purpose of this study is to analyse education, employment, and work-life experiences of visually impaired persons in expert jobs. The empirical data consists of 30 thematic interviews (24 visually impaired persons, 1 family-member of a visually impaired person, 5 persons working with diversity issues), of supplementary articles, and of statistics on the socio-economic status of the visually impaired. The interviewees experiences of education and employment have been analysed by a qualitative method. The analysis has been deepened by reflecting it against the recent discussion on the concept of diversity. The author s methodological choice as a disability researcher has been to treat the interviewees as co-researchers rather than objects of research. Accessibility in its different forms is a prerequisite of diversity in the workplace, and this study examines what kind of accessibility is required by visually impaired professionals. Access to working life depends on the attitudes prejudices and expectations that society has towards a minority group. Social accessibility is connected with internal relationships in the workplace, and achieving social accessibility is a bilateral process. Information technology has revolutionised the visually impaired people s possibilities of accessing information and performing expert tasks. Accessible environment, good mobility skills, and transportation services enable visually impaired employees to get to their workplaces and to navigate there with ease. Integration has raised the level of education and widened the selection of career options for the visually impaired. However, even visually impaired people with academic degrees often need employment support services. Visually impaired professionals are mainly employed in the public and third sector. Achieving diversity in the labour market is a multiactor process. Social support services are needed, as well as courage and readiness from employers to hire people with disabilities. The organisations of the visually impaired play an important role in affecting the attitudes and providing peer support. Visually impaired employees need good professional skills, blindness skills, and social courage, and they need to be comfortable with their disability. In the workplace, diversity may actualise as diverse ways of working: the work is done by using technical aids or other means of compensating for the lack of eyesight. When an employee must find compensatory solutions for disability-related limitations at work, this will also develop his/her problem-solving abilities. Key words: visually impaired, diversity, accessibility, working life

A Relationship Mediated Theory of Internal Marketing (summary section only)

This report presents a new theory of internal marketing. The thesis has developed as a case study in retrospective action research. This began with the personal involvement of the author in an action research project for customer service improvement at a large Australian retail bank. In other words, much of the theory generating ‘research’ took place after the original project ‘action’ had wound down. The key theoretical proposition is that internal marketing is a relationship development strategy for the purpose of knowledge renewal. In the banking case, exchanges of value between employee participants emerged as the basis for relationship development, with synergistic benefits for customers, employees and the bank. Relationship development turned out to be the mediating variable between the learning activity of employee participants at the project level and success in knowledge renewal at the organisational level. Relationship development was also a pivotal factor in the motivation and customer consciousness of employees. The conclusion reached is that the strength of relationship-mediated internal marketing is in combining a market focused commitment and employee freedom in project work to achieve knowledge renewal. The forgotten truth is that organisational knowledge can be renewed through dialogue and learning, through being trustworthy, and by gaining the trust of employees in return.

Critical Incidents in Internal Relationships

Critical incidents have had an important role in service quality and service management research. The focus of critical-incident studies has gradually shifted from separate acts and episodes towards relationships, and even switching from one relationship to another. The Critical Incident Technique has mainly been used when studying the service sector, concentrating on the customer's perception of critical incidents. Although some studies have considered the perceptions of employees important, critical incidents have not been considered a tool for studying internal relationships to any larger extent. This paper takes a process approach and shifts the focus from an external to an internal setting. It puts forward a new technique for analysing internal relationships from a critical-incident perspective. The technique captures the dynamism in relationships through considering internal critical incidents as micro-processes affecting not only internal but also external relationships.

The Far Eastern Question at the Washington Conference (1921-1922) with an outline of its implications for internal politics in China

This dissertation is a narrative account of the negotiations concerning the question of the Far East and the Shandong issue at the Washington Conference, leading to treaties, agreements and resolutions. In this dissertation, a certain stress is laid on the interaction between the Conference and the internal situation in China, particularly concerning the question of the implications of the Conference for Cabinet politics in Peking. Through the narrative account of the Conference, the general aim is an attempt to reassess the achievements of the Washington Conference. Too often the Washington Conference has been viewed negatively. The political aim behind the legal framework was to open the door to China as a sovereign State member of the international community whose territorial integrity was internationally recognized, despite its chaotic internal situation. It is undeniable that the Washington Conference opened a new chapter in modern Chinese history. The violations of the agreements concerning China that occurred in the 1930s should not lead to the belief that these agreements were of no value. Peace may not be lasting and evolves according to circumstances; agreements are transitory, and new situations need new arrangements. This dissertation tries to demonstrate that the agreements in themselves were not the cause of their failure, but the failure was due to the lack of determination on the part of the Signatories Powers to defend them.